Buying Photoshop from the US

So I'm looking to buy Photoshop CSx as I'm currently using Elements 8 but would like the extras that only come with the `grown up` version like 16/32bit support to name just one.

Ideally, I would like to get CS4 or even a cheap CS3 and upgrade but I finding getting hold of an older version that even remotely looks legit is impossible. Even Amazon seem to be rife with knock off versions from various marketplace sellers so I'm not even going there.

I can't really afford £561 that Adobe UK would want for an upgrade to CS5 so I thought I would look to the US for a cheaper version. I'm not going to start ranting about the UK v US prices as it's been done to death already

i spoke to Adobe about this and they informed me that there would be no problem in upgrading a UK Elements 8.0 to a US CS5.